Stan Wawrinka held off an injured Rafael Nadal to win his first Grand Slam title with a 6-3, 6-2, 3-6, 6-3 victory Sunday in the Australian Open final.

The 28-year-old Swiss player had never taken a set off Nadal in 12 previous meetings, but attacked from the start at Melbourne Park against the 13-time major winner.

Nadal appeared to be on the verge of retiring in the second set, when he hurt his back and needed a medical time out, but recovered slowly after getting treatment to push it to four sets.

Nadal was a hot favorite to win the title at Melbourne Park and become the first man to win each of the four Grand Slam tournaments twice in the Open era — instead, his injury curse struck again in Australia.

"Rafa, I'm really sorry for you, I hope your back is going to be fine, you're a really great guy, good friend and really amazing champion," Wawrinka said as he accepted his first major trophy. "Last year I had a crazy match, I lost it. I was crying a lot after the match. But in one year a lot happened — I still don't know if I'm dreaming or not but we'll see tomorrow morning."

Warwinka lost in five sets to Novak Djokovic in the fourth round of the 2013 Australian Open, in the longest Grand Slam match of the season. Djokovic went on to win the title, and beat Wawrinka again in five sets in the U.S. Open semifinals.

But Wawrinka avenged those losses this time, beating three-time defending champion Djokovic in the quarterfinals.

After beating the No. 1 and No. 2-ranked players to win the title, Wawrinka will move from No. 8 to No. 3 in the rankings. He'll surpass 17-time Grand Slam winner Roger Federer, who lost to Nadal in the semifinals, to become the highest-ranked Swiss player for the first time in his career.

"I need to say many thanks to Stan, you really deserve it," Nadal said. "Luck was against me today but you really deserve it.

"It has been a very emotional two weeks — I'm sorry to finish this way I tried very, very hard — this year was one of the more emotional tournaments in my career."

Nadal has had a terrible stretch with injuries at the Australian Open, and has described it as his unluckiest Grand Slam. He missed the 2013 edition during a seven-month layoff with knee injuries and illness, and his quarterfinal losses in 2010 and 2011 were affected by injuries.

There hadn't been a retirement in a men's final here since the 1990 Australian Open when Stefan Edberg quit in the third, after splitting the first two sets with Ivan Lendl.

When Nadal took a medical timeout after falling behind a set and a break, and returned to a chorus of boos without a shirt after 7 minutes, it seemed that a retirement was on the cards.

Wawrinka was aggravated during the time out, demanding that officials tell him why Nadal needed the break. And he came out aggressively to finish off the second set.

Nadal was on the verge of tears at times, and clutched at his back and tried to stretch. He needed more treatment on the side of the court after falling behind 4-1 in the second.

Nadal saved a set point in the seventh game and sat with his face in his hands at the changeover, before Wawrinka came out to serve out the set for a 2-0 lead.

By this time the crowd started getting behind Nadal again, cheering him to continue.

He saved breakpoints to hold in the opening game of the third set and then broke Wawrinka and held for a 3-0 lead.

He won the third set as Wawrinka's errors started escalating and he appeared unable to handle the pressure of being in his first Grand Slam final, and with an injured opponent on the other side of the net.

After an exchange of breaks in the fourth, Wawrinka composed himself to break Nadal and then serve it out in 2 hours, 21 minutes.